The Dow Jones fell for the fourth day and other indexes ended well down on Wednesday after the Federal Reserve reiterated concerns about the economic outlook.
As expected, the Fed left the federal funds rate at almost zero and said it would continue a programme of purchasing U.S. government bonds and mortgage-related debt.
However, stocks retreated after a statement said the Fed did not suggest that it sees any notable recovery any time soon. The statement said the economy was likely to remain weak for a time, but the pace of the contraction was slowing.
All three major stock indexes were solidly higher before the statement was issued.
The Dow Jones industrial average ended down 23.05 points, or 0.28%, at 8,299.86.
Standard & Poor's 500 Index was up 5.84 points, or 0.65%, at 900.94. The Nasdaq Composite Index was up 27.42 points, or 1.55%, at 1,792.34.
Trading volume was below average on the New York Stock Exchange, with about 1.10 billion shares changing hands - compared to last year's estimated daily average of 1.49 billion.
About 2.16 billion shares were traded on the Nasdaq - below last year's daily average of 2.28 billion.